(1) Field of the Invention
The present invention relates to a liquid crystal display device, and in particular, to a liquid crystal display device in an irregular form (that is, not rectangular) where the outer shape of the liquid crystal display panel in a plane has at least one corner that is not 90°.
(2) Description of the Related Art
In conventional liquid crystal display devices, a rectangular liquid crystal display panel is generally used. Recently, however, liquid crystal display devices in an irregular form where the outer shape of the liquid crystal display panel in a plane has a corner that is not 90° have been required for large scale monitors, display devices for entertainment, display devices for industrial machinery, and liquid crystal display devices mounted in cars.
International Unexamined Patent Publication WO2008/062575 is a prior art document that shows an example of a liquid crystal display device in an irregular form. FIG. 1 shows a liquid crystal display panel LCP used for a liquid crystal display device in an irregular form and how cushion tapes (CT1, CT2) are pasted to the rear of the liquid crystal display panel. AR denotes the image display area.
As shown in FIG. 3, which is a cross-sectional diagram along single-dotted chain line B-B′ of FIG. 1, the cushion tapes (CT1, CT2) are placed between the liquid crystal display panel LCP and the frame FR for supporting the liquid crystal display panel so as to prevent foreign substances or dust from entering between the liquid crystal display panel and the backlight BL. In addition, such cushion tapes are used in lateral electrical field type liquid crystal display panels in order to prevent external stress from being applied to a local area.
In the case where a liquid crystal display device is rectangular, cushion tapes are pasted along the four sides of the outer shape of the liquid crystal display panel so that the cushion tapes are made to make close contact with each other in the corners of the outer shape, which makes it possible for the path through which foreign substances enter to be shielded. However, as shown in FIG. 1 and FIG. 2, which shows an enlargement of the dotted portion A in FIG. 1, liquid crystal display devices in an irregular form have a liquid crystal display panel with corners that are not 90° (elliptical dotted line portion in FIG. 1). As shown in FIG. 2, a gap (arrow C) is created between the cushion tapes (CT1, CT2) in these corners, which may allow a foreign substance to enter.